Faulty Ram?

I have had this Samsung ram in my comp for a while. Well,I installed an old game and seconds later it started to crashes and I get an error saying that memory x can't be read. I find out that the game won't work for Windows XP and I get a ptach. I install the patch incorrectly (i know it was dumb) and a bunch of other software starts slowing down and I get the same message about memory after reinstalling some of it.
So, now I think I may have some faulty memory and I want to know if this is a common problem and how I can find out which piece to replace. Any other suggestions would also be helpful. Thanks.